diff --git a/CInterface/Battling/Creature.cpp b/CInterface/Battling/Creature.cpp
index e735939..da97070 100644
--- a/CInterface/Battling/Creature.cpp
+++ b/CInterface/Battling/Creature.cpp
@@ -47,8 +47,6 @@ SIMPLE_GET_FUNC_SMART_PTR(Creature, GetBattle, Battle*);
 SIMPLE_GET_FUNC_SMART_PTR(Creature, GetBattleSide, BattleSide*);
 SIMPLE_GET_FUNC(Creature, IsOnBattleField, bool);
 export const char* CreatureLib_Creature_GetNickname(Creature* p) { return p->GetNickname().c_str(); }
-export size_t CreatureLib_Creature_GetTypesCount(Creature* p) { return p->GetTypes().Count(); }
-export const uint8_t* CreatureLib_Creature_GetTypes(Creature* p) { return p->GetTypes().RawData(); }
 export bool CreatureLib_Creature_HasType(Creature* p, uint8_t type) { return p->HasType(type); }
 SIMPLE_GET_FUNC(Creature, GetMaxHealth, uint32_t);
 export uint8_t CreatureLib_Creature_ChangeLevelBy(Creature* p, int8_t level) { Try(p->ChangeLevelBy(level);) }
diff --git a/CInterface/Library/TypeLibrary.cpp b/CInterface/Library/TypeLibrary.cpp
index ff79907..2ba8455 100644
--- a/CInterface/Library/TypeLibrary.cpp
+++ b/CInterface/Library/TypeLibrary.cpp
@@ -34,5 +34,5 @@ export uint8_t CreatureLib_TypeLibrary_GetSingleEffectiveness(float& out, TypeLi
 
 export uint8_t CreatureLib_TypeLibrary_GetEffectiveness(float& out, TypeLibrary* p, uint8_t attacking,
                                                         uint8_t defensive[], size_t defensiveCount) {
-    Try(out = p->GetEffectiveness(attacking, ArbUt::List<uint8_t>(defensive, defensive + defensiveCount));)
+    Try(out = p->GetEffectiveness(attacking, std::unordered_set<uint8_t>(defensive, defensive + defensiveCount));)
 }
diff --git a/src/Battling/Flow/TurnHandler.cpp b/src/Battling/Flow/TurnHandler.cpp
index 14f19af..da777e2 100644
--- a/src/Battling/Flow/TurnHandler.cpp
+++ b/src/Battling/Flow/TurnHandler.cpp
@@ -1,5 +1,6 @@
 #include "TurnHandler.hpp"
 #include <Arbutils/Assert.hpp>
+#include <unordered_set>
 #include "../../Library/Exceptions/NotImplementedException.hpp"
 #include "../ScriptHandling/ScriptMacros.hpp"
 #include "ResolveTarget.hpp"
diff --git a/src/Battling/Models/Creature.cpp b/src/Battling/Models/Creature.cpp
index 69866ac..f7e219a 100644
--- a/src/Battling/Models/Creature.cpp
+++ b/src/Battling/Models/Creature.cpp
@@ -25,6 +25,9 @@ Battling::Creature::Creature(ArbUt::BorrowedPtr<const BattleLibrary> library,
     if (_nickname.empty()) {
         _nickname = species->GetName().std_str();
     }
+    for (auto t : _variant->GetTypes()) {
+        _types.insert(t);
+    }
 }
 
 void Battling::Creature::ChangeLevelBy(int8_t amount) {
@@ -146,14 +149,10 @@ void Battling::Creature::OverrideActiveTalent(const ConstString& talent) {
     _activeTalent.reset(this->_library->LoadScript(ScriptCategory::Talent, talent));
 }
 
-const ArbUt::List<uint8_t>& Battling::Creature::GetTypes() const noexcept {
-    // HOOK: override types.
-    return this->_variant->GetTypes();
-}
+const std::unordered_set<uint8_t>& Battling::Creature::GetTypes() const noexcept { return _types; }
 
 bool Battling::Creature::HasType(uint8_t type) const noexcept {
-    auto t = GetTypes();
-    return std::find(t.begin(), t.end(), type) != t.end();
+    return std::find(_types.begin(), _types.end(), type) != _types.end();
 }
 
 size_t Battling::Creature::ScriptCount() const {
diff --git a/src/Battling/Models/Creature.hpp b/src/Battling/Models/Creature.hpp
index b49de6b..3f106d4 100644
--- a/src/Battling/Models/Creature.hpp
+++ b/src/Battling/Models/Creature.hpp
@@ -59,6 +59,8 @@ namespace CreatureLib::Battling {
         std::unique_ptr<Script> _status = nullptr;
         ScriptSet _volatile = {};
 
+        std::unordered_set<uint8_t> _types;
+
     private:
         void OnFaint();
 
@@ -109,7 +111,7 @@ namespace CreatureLib::Battling {
         const ArbUt::CaseInsensitiveConstString& GetActiveTalent() const;
 
         [[nodiscard]] bool IsFainted() const noexcept;
-        [[nodiscard]] const ArbUt::List<uint8_t>& GetTypes() const noexcept;
+        [[nodiscard]] const std::unordered_set<uint8_t>& GetTypes() const noexcept;
         [[nodiscard]] bool HasType(uint8_t type) const noexcept;
 
         uint32_t GetMaxHealth() const noexcept { return _boostedStats.GetHealth(); }
diff --git a/src/Library/TypeLibrary.cpp b/src/Library/TypeLibrary.cpp
index 215ac0f..b6cadd1 100644
--- a/src/Library/TypeLibrary.cpp
+++ b/src/Library/TypeLibrary.cpp
@@ -4,7 +4,7 @@
 
 using namespace CreatureLib::Library;
 
-float TypeLibrary::GetEffectiveness(uint8_t attacking, const ArbUt::List<uint8_t>& defensive) const {
+float TypeLibrary::GetEffectiveness(uint8_t attacking, const std::unordered_set<uint8_t>& defensive) const {
     return std::accumulate(
         defensive.begin(), defensive.end(), (float)1,
         [this, attacking](float init, uint8_t defense) { return init * GetSingleEffectiveness(attacking, defense); });
diff --git a/src/Library/TypeLibrary.hpp b/src/Library/TypeLibrary.hpp
index c3eade0..b189f4d 100644
--- a/src/Library/TypeLibrary.hpp
+++ b/src/Library/TypeLibrary.hpp
@@ -4,7 +4,7 @@
 #include <Arbutils/Collections/Dictionary.hpp>
 #include <Arbutils/Collections/List.hpp>
 #include <Arbutils/ConstString.hpp>
-#include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
 namespace CreatureLib::Library {
@@ -18,7 +18,7 @@ namespace CreatureLib::Library {
         uint8_t GetTypeId(const ArbUt::CaseInsensitiveConstString& s) const;
         uint8_t GetTypeId(uint32_t s) const;
         [[nodiscard]] float GetSingleEffectiveness(uint8_t attacking, uint8_t defensive) const;
-        [[nodiscard]] float GetEffectiveness(uint8_t attacking, const ArbUt::List<uint8_t>& defensive) const;
+        [[nodiscard]] float GetEffectiveness(uint8_t attacking, const std::unordered_set<uint8_t>& defensive) const;
 
         uint8_t RegisterType(const ArbUt::CaseInsensitiveConstString& typeName);
         uint8_t RegisterType(uint32_t typeHash);